JP3821434B2 - Battery electrode group and non-aqueous electrolyte secondary battery using the same - Google Patents

Battery electrode group and non-aqueous electrolyte secondary battery using the same Download PDF

Info

Publication number
JP3821434B2
JP3821434B2 JP2002285844A JP2002285844A JP3821434B2 JP 3821434 B2 JP3821434 B2 JP 3821434B2 JP 2002285844 A JP2002285844 A JP 2002285844A JP 2002285844 A JP2002285844 A JP 2002285844A JP 3821434 B2 JP3821434 B2 JP 3821434B2
Authority
JP
Japan
Prior art keywords
current collector
positive electrode
electrode
negative electrode
peripheral side
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
JP2002285844A
Other languages
Japanese (ja)
Other versions
JP2004127541A5 (en
JP2004127541A (en
Inventor
秀治 武澤
修司 堤
幹也 嶋田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Corp
Panasonic Holdings Corp
Original Assignee
Panasonic Corp
Matsushita Electric Industrial Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Panasonic Corp, Matsushita Electric Industrial Co Ltd filed Critical Panasonic Corp
Priority to JP2002285844A priority Critical patent/JP3821434B2/en
Priority to US10/664,879 priority patent/US7425386B2/en
Priority to EP03021956.2A priority patent/EP1437779B1/en
Priority to CNB031327192A priority patent/CN1231983C/en
Publication of JP2004127541A publication Critical patent/JP2004127541A/en
Publication of JP2004127541A5 publication Critical patent/JP2004127541A5/ja
Application granted granted Critical
Publication of JP3821434B2 publication Critical patent/JP3821434B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • H01M10/0431—Cells with wound or folded electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Description

【０００１】
【発明の属する技術分野】
本発明は、非水電解液二次電池の生産性および信頼性の向上に関する。
【０００２】
【従来の技術】
近年、電子機器のポータブル化やコードレス化の進展に伴い、電子機器の駆動用電源となる二次電池の高エネルギー密度化や小型・軽量化の要望が高まっている。このような要望に対し、小型・軽量でありながら急速充電が可能で、高エネルギー密度を有する非水電解液二次電池が開発され、リチウムイオン二次電池がその主流となっている。
【０００３】
代表的な非水電解液二次電池は、正極および負極をセパレータを介して捲回してなる渦巻き状の電極群、非水電解液、ならびに前記電極群と非水電解液とを収容する電池ケースからなる。正極は、アルミニウム製集電体および前記集電体上に設けられた正極合剤層からなり、正極活物質には、リチウム含有遷移金属化合物、例えばＬｉＣｏＯ2 が用いられる。また、負極は、銅製集電体および前記集電体上に形成された負極合剤層からなり、負極活物質には、例えば炭素材料が用いられる。この電池は、電極へのリチウムイオンの挿入・離脱を利用したものであり、高率充放電を可能にするために、正極と負極との対向面積を大きくする工夫がなされている。
【０００４】
しかしながら、電子機器の高機能化と消費電力の増加に伴い、さらなる高容量化・高エネルギー密度化が強く要望されている。このため、セパレータや集電体を薄くして正負極間の距離を狭め、容量に寄与しない電池ケース内空間を少なくする工夫もなされている。
【０００５】
このような渦巻き状の電極群が非水電解液とともに電池ケースに収納された電池では、充電の際、負極の膨張および電極群の変形が起こる。そして、局部的に極板が圧迫され、リチウムイオンを均一に挿入・離脱できない部分が生じる。その部分では、正極の電位が上昇しやすく、充放電の際、あるいは充電状態での高温保存時に、正極活物質中の遷移金属が溶出して負極上に析出する。析出金属は、やがてセパレータを貫通し、内部短絡が発生する。これによって異常な電圧低下が起こるため、電池の信頼性が低下することになる。
【０００６】
これまでに、信頼性を向上させる目的で、正極合剤層の端部とそれに対向する負極合剤層との間に、イオン絶縁体を配設することが提案されている（例えば、特許文献１、２参照。）。これは、イオン絶縁体によって、リチウムの挿入・脱離を含む充電反応そのものを抑制し、正極の局部的な電位上昇を抑え、内部短絡を防止しようとするものである。しかし、この提案では正極合剤層と負極合剤層との間にイオン絶縁体を配設するため、後述のような内部短絡を防止することはできない。また、イオン絶縁体が直接正極合剤層あるいは負極合剤層を覆ってしまうため、電極反応が阻害され、容量が低下する。
【０００７】
図３に、従来の渦巻き状電極群の部分断面図を示す。
この図は、電池ケース１４と隣接する電極群の最外周近辺を示している。図３では、電極群の最外周に正極１１が位置しており、最外周では正極集電体１１ａが両面で露出している。また、その一周内側では、正極集電体１１ａの内側片面だけに正極合剤層１１ｂが形成されている。最外周の正極集電体露出部には、正極リード１１ｃが溶接されている。そして、正極リード１１ｃから一定の間隔を置いてより内周側に、セパレータ１３の外周側の長手端部１９が位置している。正極１１の内側には、セパレータ１３を介して、負極１２が配置されている。負極１２では、電極群の最外周近辺においても負極集電体１２ａの両面に負極合剤層１２ｂが形成されている。
【０００８】
短絡部位１５は、正極合剤層１１ｂと負極合剤層１２ｂとの間のセパレータに形成される。短絡部位１５は、セパレータ１３の長手端部１９および正極リード１１ｃの周縁部がそれぞれ電極群内で形成する段差部分と、正極合剤層１１ｂと正極集電体１１ａを介して対向している。このような構造の電極群においては、充電時の負極の膨張により、電極群の内圧が上昇したり、電極群が電池ケース内壁から圧力を受けると、段差部分に対向する部分は局部的な圧力を受ける。局部的な圧力を受けた部分では、正極１１と負極１２との極間距離が小さくなり、電極反応が集中しやすくなる。そして、狭くなった極間に介在するセパレータに短絡部位１５が形成される。
【０００９】
図４は、図３に示す電極群内の負極における短絡部位１５を含む領域Ａを、矢印Ｘ方向から見た正面図である。負極幅は正極幅よりも一回り大きくなっている。負極と正極との対向領域の境界線１６上では、局部的に正極電位が上昇しやすく、正極活物質の溶出が起こりやすい。領域Ａとセパレータ（図示せず）の長手端部との対向領域の境界線１７上や、領域Ａと正極リードとの対向領域の境界線１８上でも同様である。溶出した正極活物質は、極間距離の小さい位置において、負極上に集中して析出する、従って、短絡部位１５は、境界線１６と、境界線１７、１８との交点に最も形成されやすい。
【００１０】
【特許文献１】
特開平５−１８２６９１号公報
【特許文献２】
特開平１１−２７３７３９号公報
【００１１】
【発明が解決しようとする課題】
上述から明らかなように、高エネルギー密度の非水電解液二次電池においては、電極反応の不均一性を低減し、正極活物質の溶出による内部短絡を防止する必要がある。また、初期電池の電圧不良や、充電された電池の高温保存による異常な電圧低下を防止する必要がある。本発明は、これらの課題を鑑みたものである。
【００１２】
【課題を解決するための手段】
本発明は、正極と負極とを、それらの間にセパレータを介して捲回してなる渦巻き状の電極群であって、前記正極は、正極集電体および前記正極集電体上に設けられた少なくとも１つの正極合剤層からなり、前記負極は、負極集電体および前記負極集電体上に設けられた少なくとも１つの負極合剤層からなる電池用電極群に関する。
【００１３】
前記電極群の最外周を構成する前記正極および前記負極のどちらか一方において、外周側の長手端部（長手方向における端部）から内周側の所定位置までの領域が、両面に合剤層が設けられていない両面集電体露出部であり、前記両面集電体露出部に続くさらに内周側の所定位置までの領域が、内側片面のみに合剤層が設けられている片面集電体露出部であり、前記両面集電体露出部と前記片面集電体露出部とが、少なくとも部分的に、前記最外周を構成しない他方の電極を介さずに対向している。
【００１４】
前記両面集電体露出部には、リードが接続されており、前記リードよりも内周側に、前記セパレータの外周側の長手方向における端部が位置している。
【００１５】
前記最外周を構成する電極の外周側の長手方向における端部および前記セパレータの外周側の長手方向における端部がそれぞれ前記電極群内で形成する段差部分は、内側から絶縁部材により覆われている。
【００１６】
前記絶縁部材は、前記段差部分と対向する片面集電体露出部の外側に、貼り付けられていることが好ましい。
【００１７】
本発明は、また、上記の渦巻き状の電極群、非水電解液および前記電極群と前記非水電解液とを収容する電池ケースからなる非水電解液二次電池に関する。
なお、本発明では、電極群を構成する正極、負極およびセパレータにおいて、捲回方向に対して垂直方向の端部を長手端部とする。一方、捲回方向に対して平行方向の端部を短手端部とする。
【００１８】
【発明の実施の形態】
本発明の実施形態の一例について図１、２を参照しながら説明する。
図１に、本発明の渦巻き状電極群の部分断面図を示す。
この電極群は、正極と負極とを、それらの間にセパレータを介して捲回してなる渦巻き状の電極群である。図１は、電池ケース４と隣接する電極群の最外周近辺を示している。電極群の最外周に正極１が位置しており、最外周では正極集電体１ａが両面で露出している。また、その一周内側では、正極集電体１ａの内側片面だけに正極合剤層１ｂが形成されている。最外周の正極集電体露出部の内側には、正極リード１ｃが溶接されている。そして、正極リード１ｃから一定の間隔を置いてより内周側に、セパレータ３の外周側の長手端部９が位置している。正極１の内側には、セパレータ３を介して、負極２が配置されている。負極２では、電極群の最外周近辺においても負極集電体２ａの両面に負極合剤層２ｂが形成されている。
【００１９】
セパレータ３の長手端部９および正極リード１ｃの周縁部は、それぞれ電極群内で段差部分を形成している。この段差部分を覆うように、絶縁部材５が配設されている。絶縁部材５は、セパレータ３や正極リード１ｃと正極集電体１ａとの間に介在させるだけでも良いが、製造工程を有利にする観点からは、セパレータ３または正極集電体１ａに貼り付けることが好ましい。
【００２０】
絶縁部材５には、例えば、基材と糊剤からなる絶縁テープを用いることができる。糊剤は基材の両面に設けてもよいが、片面だけに設ければ十分である。また、基材の片面全面に糊剤を設けてもよいが、一部の領域に設けるだけの方が作業性の観点から好ましい。また、電池が高温に曝された時のセパレータの熱収縮に起因する内部短絡を抑制する観点から、絶縁部材の耐熱温度は、セパレータよりも高い方が好ましい。
【００２１】
正極、負極およびセパレータの長手端部ならびにリードの周縁部がそれぞれ電極群内で形成する段差部分は、通常、複数存在する。段差部分を覆う絶縁部材の数は特に限定されないが、作業性の観点から、電極群の同一面内に複数の段差部分がある場合には、１つの絶縁部材でそれらすべてを覆うことが好ましい。また、図３で示したように、短絡部位は、正極と負極との対向領域の境界線上に形成される。従って、絶縁部材の幅は、少なくとも電極群において正極の上下端部よりも突出するように、正極の幅よりも大きいことが好ましい。
【００２２】
絶縁部材の厚さは、電極群の段差部分の局部的な圧迫を低減できる厚さであればよく、例えば１０〜１００μｍであることが好ましい。絶縁部材が薄過ぎると、内部短絡を抑制する効果が十分に得られず、１００μｍを超えると、電池ケースの内部空間に占める極板体積の割合が減少し、電池容量が低下する。基材と糊剤からなる絶縁テープの場合、基材の厚さは１０μｍ〜５０μｍ、糊剤の厚さは５μｍ〜３０μｍの範囲が、絶縁性、粘着性および作業性の観点から好ましい。
【００２３】
基材の材質には、ポリエチレン樹脂、ポリプロピレン樹脂などのポリオレフィン樹脂、ポリエチレンテレフタレート樹脂、ポリエーテルエーテルケトン樹脂、ポリフェニレンサルファイド樹脂、ポリアリレート樹脂、ポリアミド樹脂、ポリイミド樹脂、フッ素樹脂などを用いることができる。これらは単独で用いてもよく、複数を組み合わせて用いてもよい。また、これらの変性樹脂を用いることもできる。ガラス繊維、タルク、シリカなどの充填材を含む基材を用いることもできる。
【００２４】
糊剤には、天然ゴム、イソブチルゴム、スチレンブタジエンゴム、シリコンゴム、ウレタンゴム、アクリル樹脂などを用いることができる。これらは単独で用いてもよく、例えば積層するなど複数を組み合わせて用いてもよい。これらを変性して用いることもできる。
【００２５】
正極、負極、セパレータおよび非水電解液には、非水電解液二次電池に従来から用いられている公知のものを、特に限定なく用いることができる。すなわち、正極集電体、負極集電体、正極合剤層に含まれる正極活物質、導電剤、結着剤、増粘剤等、負極合剤層に含まれる負極活物質、結着剤、増粘剤等は、特に限定されない。
【００２６】
正極集電体には、好ましくはアルミニウム箔や、ラス加工もしくはエッチング処理された金属箔が用いられる。正極は、正極集電体の片側または両面に、正極合剤を塗布し、乾燥し、得られた極板を圧延して作製される。正極の厚さは、一般に１００μｍ〜２００μｍであり、なるべく柔軟性を有することが好ましい。正極合剤は、正極活物質、結着剤、導電剤、必要に応じて増粘剤を、分散媒と混練することで調製される。
【００２７】
また、負極集電体には、好ましくは銅箔や、ラス加工もしくはエッチング処理された金属箔が用いられる。負極は、負極集電体の片側または両面に、負極合剤を塗布し、乾燥し、得られた極板を圧延して作製される。負極の厚さは、一般に１００μｍ〜２００μｍであり、なるべく柔軟性を有することが好ましい。負極合剤は、負極活物質、結着剤、必要に応じて導電剤や増粘剤を、分散媒と混練することで調製される。
【００２８】
正極合剤および負極合剤の調製方法には、特に限定がなく、例えば、プラネタリーミキサー、ホモミキサー、ピンミキサー、ニーダー、ホモジナイザー等を用いて原料を混合する方法を採用することができる。合剤調製時に、各種分散剤、界面活性剤、安定剤等を必要に応じて原料に添加してもよい。塗工工程は、特に限定されず、合剤を、例えば、スリットダイコーター、リバースロールコーター、リップコーター、ブレードコーター、ナイフコーター、グラビアコーター、ディップコーター等を用いて、集電体に塗着することができる。そして、自然乾燥もしくはこれに近い乾燥を行う。乾燥温度は生産性を考慮すると７０〜２００℃が好ましい。圧延工程は、ロールプレス機により、極板が所定の厚さになるまで行う。
【００２９】
セパレータの厚さは、高エネルギー密度を確保する観点から、通常、１０〜３０μｍである。非水電解液に用いられる非水溶媒、溶質、添加剤も特に限定されず、すでに公知のものを用いることができる。電池ケースも特に限定されないが、一般に、上部が開口している有底円筒形ケースや角形・長円形ケースが用いられる。
【００３０】
【実施例】
以下、実施例および比較例を用いて本発明を詳細に説明するが、これらは本発明を何ら限定するものではない。
《実施例１》
図１、２、５を参照しながら説明する。
（ｉ）正極の作製
正極活物質としてコバルト酸リチウムを１００重量部、導電剤としてアセチレンブラックを３重量部、結着剤としてポリテトラフルオロエチレン（ＰＴＦＥ）の水性分散液を樹脂分で４重量部、増粘剤としてカルボキシメチルセルロース水溶液を樹脂分で０．８重量部計量し、これらを混合して、ペースト状の正極合剤を調製した。この正極合剤を、厚さ２０μｍの帯状アルミニウム箔からなる正極集電体１ａの両面に塗着し、乾燥し、得られた極板を圧延して、厚さ１８０μｍの正極１を得た。
【００３１】
電極群の最外周に位置する予定の正極１の長手端部から所定位置までの領域には、両面に正極合剤層１ｂが設けられていない両面集電体露出部５１を設け、両面集電体露出部５１に続くさらに所定位置までの領域には、片面のみに正極合剤層１ｂが設けられている片面集電体露出部５２を設けた。得られた正極１の上記長手端部近辺の断面図を図５に示す。
次いで、正極１の両面集電体露出部５１に、正極リード１ｃをスポット溶接して取り付けた。その後、正極１を１２０℃で１５分間乾燥した。
【００３２】
（ii）負極の作製
負極活物質として鱗片状黒鉛１００重量部、結着剤としてスチレンブタジエンゴム（ＳＢＲ）の水性分散液を樹脂分で４重量部、増粘剤としてカルボキシメチルセルロース水溶液を樹脂分で０．８重量部計量し、これらを混合して、ペースト状の負極合剤を調製した。この負極合剤を、厚さ１４μｍの帯状銅箔からなる負極集電体２ａの両面に塗着し、乾燥し、得られた極板を圧延して、厚さ１９６μｍの負極２を得た。
【００３３】
電極群の最内周に位置する予定の負極２の長手端部から所定位置までの領域には、片面に負極合剤層２ｂが設けられていない負極集電体露出部を設けた。そして、負極集電体露出部に、負極リード２ｃをスポット溶接して取り付けた。その後、負極２を１１０℃で１０分間乾燥した。
【００３４】
（iii）電極群の作製
このようにして得られた正極１と負極２とを、耐熱温度が１４０℃で、厚さ２０μｍのポリプロピレン製セパレータを介して、捲回して、渦巻き状の電極群を作製した。この電極群を図２に示すように、横断面が略楕円形になるようにプレスした。
【００３５】
（iv）絶縁部材の配設
次に、図１、２に示すように、電極群の最外周に位置する両面集電体露出部と、その１周内側に位置する片面集電体露出部との間の、セパレータ３よりも内側に、絶縁部材５を配設した。絶縁部材５の幅は、正極集電体１ａの幅よりも２ｍｍ大きく、正極１の上端および下端から、それぞれ１ｍｍずつ突出させた。
ここでは、絶縁部材として、厚さ２０μｍのポリフェニレンサルファイド樹脂（耐熱温度２００℃）の基材と、その片面に形成された厚さ１０μｍのウレタン樹脂の糊剤層からなる絶縁テープを用いた。絶縁テープは、正極１の片面集電体露出部に貼り付けた。
【００３６】
（ｖ）電池の組立
上記電極群を開口部を有する有底角形の電池ケース４に収納した。正極リード１ｃの他端部は、防爆機構を有する封口板に接続し、負極リード２ｃの他端部は、封口板の負極端子に接続した。その後、封口板の周囲と電池ケース４の開口端部とをレーザ溶接した。
【００３７】
次いで、封口板の注液孔から、電池ケース４内に、非水電解液を注液した。この非水電解液は、エチレンカーボネートとエチルメチルカーボネートとの体積比１：１の混合溶媒中に、溶質としてヘキサフルオロリン酸リチウム（ＬｉＰＦ6）を１．０モル／Ｌの濃度で溶解したものである。その後、注液孔に封栓を挿入し、封栓の周囲と封口板とをレーザ溶接することにより、電池を密封した。こうして公称容量８００ｍＡｈの角形リチウムイオン二次電池（幅５．３ｍｍ、長さ３０ｍｍ、総高４８ｍｍ）を完成した。同様の電池を１００個作製した。
【００３８】
《比較例１》
電極群に、絶縁部材の配設を行わなかったこと以外、実施例１と同様にして、公称容量８００ｍＡｈの角形リチウムイオン二次電池（幅５．３ｍｍ、長さ３０ｍｍ、総高４８ｍｍ）を作製した。同様の電池を１００個作製した。
【００３９】
［評価］
実施例１および比較例１の各電池の組立直後の内部短絡の発生率（発生率Ａ：１００個中、内部短絡が発生した電池の個数）、および充電状態で高温保存試験を行った後の内部短絡の発生率（発生率Ｂ：１０個中、内部短絡が発生した電池の個数）を評価した。結果を表１に示す。
【００４０】
なお、高温保存試験では、各電池を２０℃の環境下で３．０Ｖの終止電圧まで１６０ｍＡの定電流で放電した後、充電電圧４．２Ｖ、充電電流８０ｍＡの定電流定電圧充電を行った。そして、満充電状態の電池を、８０℃雰囲気下で、１週間保存した。
【００４１】
【表１】

Figure 0003821434
【００４２】
表１より、実施例１では、組立直後および高温保存後においても、内部短絡の発生率が極めて低いことがわかる。一方、比較例１では、組立直後および高温保存後の内部短絡の発生率が非常に高い。このような差違は、実施例１においてのみ、電極群の最外周に位置する両面集電体露出部と、その１周内側に位置する片面集電体露出部との間に、絶縁部材５を配設したことによる効果と考えられる。すなわち、実施例１では、セパレータの長手端部ならびに正極リードの周縁部が電極群内で形成する段差部分において、局部的な圧迫が緩和され、電極反応の不均一性が低減し、正極活物質の溶出が抑制され、内部短絡が防止されたものと考えられる。
【００４３】
【発明の効果】
本発明によれば、電極群内で形成される段差部分において生じる局部的な圧迫が緩和され、電極反応の不均一性が低減するため、電池の内部短絡が防止される。従って、高エネルギー密度の非水電解液二次電池の生産性および信頼性が向上する。
【図面の簡単な説明】
【図１】本発明の実施形態の一例に係る電極群の部分横断面図である。
【図２】本発明の実施形態の一例に係る電極群を用いた非水電解液二次電池の概略構成図である。
【図３】従来の電極群の部分横断面図である。
【図４】図３に示す電極群内の負極における短絡部位１５を含む領域Ａを、矢印Ｘ方向から見た正面図である。
【図５】本発明の実施形態の一例に係る電極群に用いる正極の断面図である。
【符号の説明】
１、１１ 正極
１ａ、１１ａ 正極集電体
１ｂ、１１ｂ 正極合剤層
１ｃ、１１ｃ 正極リード
２、１２ 負極
２ａ、１２ａ 負極集電体
２ｂ、１２ｂ 負極合剤層
２ｃ 負極リード
３、１３ セパレータ
４、１４ 電池ケース
５ 絶縁部材
９、１９ セパレータの長手端部
１５ 短絡部位
１６ 負極と正極との対向領域の境界線
１７ 領域Ａとセパレータの長手端部との対向領域の境界線
１８ 領域Ａと正極リードとの対向領域の境界線
５１ 両面集電体露出部
５２ 片面集電体露出部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement in productivity and reliability of a nonaqueous electrolyte secondary battery.
[0002]
[Prior art]
In recent years, with the progress of portable and cordless electronic devices, there is a growing demand for higher energy density, smaller size, and lighter weight of secondary batteries serving as power sources for driving electronic devices. In response to such a demand, a non-aqueous electrolyte secondary battery having a high energy density that can be rapidly charged while being small and lightweight has been developed, and a lithium ion secondary battery has become the mainstream.
[0003]
A typical non-aqueous electrolyte secondary battery includes a spiral electrode group obtained by winding a positive electrode and a negative electrode with a separator interposed therebetween, a non-aqueous electrolyte solution, and a battery case containing the electrode group and the non-aqueous electrolyte solution. Consists of. The positive electrode includes an aluminum current collector and a positive electrode mixture layer provided on the current collector, and a lithium-containing transition metal compound such as LiCoO 2 is used as the positive electrode active material. The negative electrode includes a copper current collector and a negative electrode mixture layer formed on the current collector. For example, a carbon material is used as the negative electrode active material. This battery utilizes insertion / extraction of lithium ions to / from an electrode, and has been devised to increase the facing area between the positive electrode and the negative electrode in order to enable high-rate charging / discharging.
[0004]
However, with the increase in functionality and power consumption of electronic devices, there is a strong demand for higher capacity and higher energy density. For this reason, the separator and the current collector are made thinner so that the distance between the positive and negative electrodes is narrowed to reduce the space in the battery case that does not contribute to the capacity.
[0005]
In a battery in which such a spiral electrode group is housed in a battery case together with a non-aqueous electrolyte, the negative electrode expands and the electrode group deforms during charging. Then, the electrode plate is locally pressed, and a portion where lithium ions cannot be uniformly inserted / removed is generated. At that portion, the potential of the positive electrode is likely to rise, and the transition metal in the positive electrode active material is eluted and deposited on the negative electrode during charge / discharge or storage at high temperature in the charged state. The deposited metal eventually penetrates the separator, causing an internal short circuit. As a result, an abnormal voltage drop occurs, which reduces the reliability of the battery.
[0006]
In the past, for the purpose of improving reliability, it has been proposed to dispose an ion insulator between the end portion of the positive electrode mixture layer and the negative electrode mixture layer facing the end portion (for example, Patent Documents). 1 and 2). This is intended to suppress the charging reaction itself including insertion / extraction of lithium by the ion insulator, suppress a local potential increase of the positive electrode, and prevent an internal short circuit. However, in this proposal, since an ion insulator is disposed between the positive electrode mixture layer and the negative electrode mixture layer, an internal short circuit as described later cannot be prevented. Further, since the ion insulator directly covers the positive electrode mixture layer or the negative electrode mixture layer, the electrode reaction is hindered and the capacity is reduced.
[0007]
In FIG. 3, the fragmentary sectional view of the conventional spiral electrode group is shown.
This figure shows the vicinity of the outermost periphery of the electrode group adjacent to the battery case 14. In FIG. 3, the positive electrode 11 is located on the outermost periphery of the electrode group, and the positive electrode current collector 11a is exposed on both surfaces at the outermost periphery. Further, on the inner side of the circumference, the positive electrode mixture layer 11b is formed only on the inner surface of the positive electrode current collector 11a. A positive electrode lead 11c is welded to the outermost positive electrode current collector exposed portion. The longitudinal end 19 on the outer peripheral side of the separator 13 is located on the inner peripheral side at a certain distance from the positive electrode lead 11c. A negative electrode 12 is arranged inside the positive electrode 11 with a separator 13 interposed therebetween. In the negative electrode 12, the negative electrode mixture layer 12b is formed on both surfaces of the negative electrode current collector 12a even in the vicinity of the outermost periphery of the electrode group.
[0008]
The short-circuit part 15 is formed in the separator between the positive electrode mixture layer 11b and the negative electrode mixture layer 12b. The short-circuit portion 15 is opposed to the step portion formed in the electrode group by the longitudinal end portion 19 of the separator 13 and the peripheral edge portion of the positive electrode lead 11c, via the positive electrode mixture layer 11b and the positive electrode current collector 11a. In the electrode group having such a structure, when the internal pressure of the electrode group rises due to the expansion of the negative electrode during charging, or when the electrode group receives pressure from the inner wall of the battery case, the portion facing the stepped portion is localized pressure. Receive. In the portion that has received local pressure, the distance between the positive electrode 11 and the negative electrode 12 becomes small, and the electrode reaction tends to concentrate. And the short circuit site | part 15 is formed in the separator interposed between the poles which became narrow.
[0009]
FIG. 4 is a front view of the region A including the short-circuited portion 15 in the negative electrode in the electrode group shown in FIG. The negative electrode width is slightly larger than the positive electrode width. On the boundary line 16 of the opposing area between the negative electrode and the positive electrode, the positive electrode potential tends to rise locally, and the positive electrode active material tends to elute. The same applies to the boundary line 17 of the opposing region between the region A and the longitudinal end of the separator (not shown) and the boundary line 18 of the opposing region between the region A and the positive electrode lead. The eluted positive electrode active material concentrates and deposits on the negative electrode at a position where the distance between the electrodes is small. Therefore, the short circuit site 15 is most easily formed at the intersection of the boundary line 16 and the boundary lines 17 and 18.
[0010]
[Patent Document 1]
JP-A-5-182691 [Patent Document 2]
Japanese Patent Laid-Open No. 11-273739
[Problems to be solved by the invention]
As is clear from the above, in the high energy density non-aqueous electrolyte secondary battery, it is necessary to reduce the non-uniformity of the electrode reaction and prevent internal short circuit due to elution of the positive electrode active material. In addition, it is necessary to prevent voltage failure of the initial battery and abnormal voltage drop due to high temperature storage of the charged battery. The present invention has been made in view of these problems.
[0012]
[Means for Solving the Problems]
The present invention is a spiral electrode group in which a positive electrode and a negative electrode are wound with a separator interposed therebetween, and the positive electrode is provided on the positive electrode current collector and the positive electrode current collector. It consists of at least one positive electrode mixture layer, and the negative electrode relates to a battery electrode group consisting of a negative electrode current collector and at least one negative electrode mixture layer provided on the negative electrode current collector.
[0013]
In either of the positive electrode and the negative electrode constituting the outermost periphery of the front Symbol electrode group, the area up to a predetermined position on the inner circumferential side from the longitudinal end portion of the outer peripheral side (an end portion in the longitudinal direction), material mixture on both sides A double-sided current collector exposed portion that is not provided with a layer, and a region up to a predetermined position on the inner peripheral side following the double-sided current collector exposed portion is provided with a mixture layer only on the inner side. a collector exposed portion, and the double-sided collector exposed portion and the one side current collector exposed portion, it is opposed without passing through the other side of the electrode not configured at least in part, a pre-Symbol outermost.
[0014]
A lead is connected to the double-sided current collector exposed portion , and an end portion in the longitudinal direction on the outer peripheral side of the separator is located on the inner peripheral side of the lead.
[0015]
The step portions formed in the electrode group by the end portion in the longitudinal direction on the outer peripheral side of the electrode constituting the outermost periphery and the end portion in the longitudinal direction on the outer peripheral side of the separator are each covered with an insulating member from the inside. .
[0016]
The insulating member is preferably attached to the outside of the single-sided current collector exposed portion that faces the stepped portion .
[0017]
The present invention also relates to a non-aqueous electrolyte secondary battery comprising the spiral electrode group, the non-aqueous electrolyte, and a battery case that houses the electrode group and the non-aqueous electrolyte.
In the present invention, in the positive electrode, the negative electrode, and the separator constituting the electrode group, the end in the direction perpendicular to the winding direction is the long end. On the other hand, the end in the direction parallel to the winding direction is the short end.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
An example of an embodiment of the present invention will be described with reference to FIGS.
In FIG. 1, the fragmentary sectional view of the spiral electrode group of this invention is shown.
This electrode group is a spiral electrode group formed by winding a positive electrode and a negative electrode through a separator between them. FIG. 1 shows the vicinity of the outermost periphery of the electrode group adjacent to the battery case 4. The positive electrode 1 is located on the outermost periphery of the electrode group, and the positive electrode current collector 1a is exposed on both surfaces at the outermost periphery. Further, on the inner side of the circumference, the positive electrode mixture layer 1b is formed only on the inner surface of the positive electrode current collector 1a. A positive electrode lead 1 c is welded inside the outermost positive electrode current collector exposed portion. The longitudinal end portion 9 on the outer peripheral side of the separator 3 is located further on the inner peripheral side at a certain distance from the positive electrode lead 1c. A negative electrode 2 is disposed inside the positive electrode 1 with a separator 3 interposed therebetween. In the negative electrode 2, the negative electrode mixture layer 2b is formed on both surfaces of the negative electrode current collector 2a even near the outermost periphery of the electrode group.
[0019]
The longitudinal end portion 9 of the separator 3 and the peripheral edge portion of the positive electrode lead 1c form step portions in the electrode group. An insulating member 5 is disposed so as to cover the stepped portion. The insulating member 5 may be merely interposed between the separator 3 or the positive electrode lead 1c and the positive electrode current collector 1a, but is attached to the separator 3 or the positive electrode current collector 1a from the viewpoint of making the manufacturing process advantageous. Is preferred.
[0020]
For the insulating member 5, for example, an insulating tape made of a base material and a paste can be used. The paste may be provided on both sides of the substrate, but it is sufficient to provide it on only one side. Further, the paste may be provided on the entire surface of one side of the base material, but it is preferable to provide the adhesive only in a part of the region from the viewpoint of workability. Further, from the viewpoint of suppressing an internal short circuit due to the thermal contraction of the separator when the battery is exposed to a high temperature, the heat resistance temperature of the insulating member is preferably higher than that of the separator.
[0021]
In general, there are a plurality of step portions formed by the longitudinal end portions of the positive electrode, the negative electrode, and the separator, and the peripheral portion of the lead in the electrode group. The number of insulating members that cover the stepped portions is not particularly limited, but from the viewpoint of workability, when there are a plurality of stepped portions in the same plane of the electrode group, it is preferable to cover them all with one insulating member. Further, as shown in FIG. 3, the short-circuit portion is formed on the boundary line of the opposing region between the positive electrode and the negative electrode. Therefore, the width of the insulating member is preferably larger than the width of the positive electrode so as to protrude from the upper and lower ends of the positive electrode at least in the electrode group.
[0022]
The thickness of the insulating member may be any thickness that can reduce local compression of the stepped portion of the electrode group, and is preferably 10 to 100 μm, for example. If the insulating member is too thin, the effect of suppressing the internal short circuit cannot be sufficiently obtained, and if it exceeds 100 μm, the proportion of the electrode plate volume in the internal space of the battery case decreases, and the battery capacity decreases. In the case of an insulating tape composed of a base material and a paste, the thickness of the base material is preferably 10 μm to 50 μm, and the thickness of the paste is preferably 5 μm to 30 μm from the viewpoints of insulation, adhesiveness and workability.
[0023]
As the material of the base material, polyolefin resins such as polyethylene resin and polypropylene resin, polyethylene terephthalate resin, polyether ether ketone resin, polyphenylene sulfide resin, polyarylate resin, polyamide resin, polyimide resin, fluorine resin, and the like can be used. These may be used alone or in combination. These modified resins can also be used. A substrate containing a filler such as glass fiber, talc, or silica can also be used.
[0024]
As the paste, natural rubber, isobutyl rubber, styrene butadiene rubber, silicon rubber, urethane rubber, acrylic resin, or the like can be used. These may be used singly, or may be used in combination of a plurality of layers such as stacking. These can be used after being modified.
[0025]
As the positive electrode, the negative electrode, the separator, and the non-aqueous electrolyte, known ones conventionally used in non-aqueous electrolyte secondary batteries can be used without particular limitation. That is, a positive electrode current collector, a negative electrode current collector, a positive electrode active material contained in the positive electrode mixture layer, a conductive agent, a binder, a thickener, etc., a negative electrode active material contained in the negative electrode mixture layer, a binder, A thickener etc. are not specifically limited.
[0026]
As the positive electrode current collector, an aluminum foil or a metal foil that has been subjected to lath processing or etching treatment is preferably used. The positive electrode is produced by applying a positive electrode mixture to one side or both sides of a positive electrode current collector, drying the resultant, and rolling the obtained electrode plate. The thickness of the positive electrode is generally 100 μm to 200 μm and preferably has flexibility as much as possible. The positive electrode mixture is prepared by kneading a positive electrode active material, a binder, a conductive agent, and, if necessary, a thickener with a dispersion medium.
[0027]
The negative electrode current collector is preferably a copper foil or a metal foil that has been subjected to lath processing or etching. The negative electrode is produced by applying a negative electrode mixture on one side or both sides of a negative electrode current collector, drying, and rolling the obtained electrode plate. The thickness of the negative electrode is generally 100 μm to 200 μm and preferably has flexibility as much as possible. The negative electrode mixture is prepared by kneading a negative electrode active material, a binder, and, if necessary, a conductive agent and a thickener with a dispersion medium.
[0028]
The method for preparing the positive electrode mixture and the negative electrode mixture is not particularly limited, and for example, a method of mixing raw materials using a planetary mixer, a homomixer, a pin mixer, a kneader, a homogenizer, or the like can be employed. During preparation of the mixture, various dispersants, surfactants, stabilizers and the like may be added to the raw materials as necessary. The coating process is not particularly limited, and the mixture is applied to the current collector using, for example, a slit die coater, reverse roll coater, lip coater, blade coater, knife coater, gravure coater, dip coater, or the like. be able to. Then, natural drying or drying close to this is performed. The drying temperature is preferably 70 to 200 ° C. in consideration of productivity. The rolling process is performed with a roll press until the electrode plate has a predetermined thickness.
[0029]
The thickness of a separator is 10-30 micrometers normally from a viewpoint of ensuring a high energy density. The nonaqueous solvent, solute, and additive used for the nonaqueous electrolytic solution are not particularly limited, and those already known can be used. The battery case is not particularly limited, but generally, a bottomed cylindrical case with an open top or a square / oval case is used.
[0030]
【Example】
EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example and a comparative example, these do not limit this invention at all.
Example 1
This will be described with reference to FIGS.
(I) Production of positive electrode 100 parts by weight of lithium cobaltate as a positive electrode active material, 3 parts by weight of acetylene black as a conductive agent, and 4 parts by weight of an aqueous dispersion of polytetrafluoroethylene (PTFE) as a binder Then, 0.8 parts by weight of a carboxymethyl cellulose aqueous solution as a thickener was weighed in the resin content, and these were mixed to prepare a paste-like positive electrode mixture. This positive electrode mixture was applied to both surfaces of a positive electrode current collector 1a made of a strip-shaped aluminum foil having a thickness of 20 μm, dried, and the obtained electrode plate was rolled to obtain a positive electrode 1 having a thickness of 180 μm.
[0031]
In a region from the longitudinal end of the positive electrode 1 scheduled to be located at the outermost periphery of the electrode group to a predetermined position, a double-sided current collector exposed portion 51 in which the positive electrode mixture layer 1b is not provided on both sides is provided, A single-side current collector exposed portion 52 in which the positive electrode mixture layer 1b is provided only on one side is provided in a region following the body exposed portion 51 to a predetermined position. A cross-sectional view of the positive electrode 1 in the vicinity of the longitudinal end is shown in FIG.
Next, the positive electrode lead 1 c was attached to the double-sided current collector exposed portion 51 of the positive electrode 1 by spot welding. Thereafter, the positive electrode 1 was dried at 120 ° C. for 15 minutes.
[0032]
(Ii) Production of negative electrode 100 parts by weight of scaly graphite as a negative electrode active material, 4 parts by weight of an aqueous dispersion of styrene butadiene rubber (SBR) as a binder, and an aqueous carboxymethyl cellulose solution as a thickener 0.8 parts by weight were weighed and mixed to prepare a paste-like negative electrode mixture. This negative electrode mixture was applied to both surfaces of a negative electrode current collector 2a made of a strip-shaped copper foil having a thickness of 14 μm, dried, and the obtained electrode plate was rolled to obtain a negative electrode 2 having a thickness of 196 μm.
[0033]
A negative electrode current collector exposed portion in which the negative electrode mixture layer 2b is not provided on one side is provided in a region from the longitudinal end portion of the negative electrode 2 scheduled to be located on the innermost periphery of the electrode group to a predetermined position. And the negative electrode lead 2c was attached to the negative electrode collector exposed part by spot welding. Thereafter, the negative electrode 2 was dried at 110 ° C. for 10 minutes.
[0034]
(Iii) Production of electrode group The positive electrode 1 and the negative electrode 2 thus obtained were wound through a polypropylene separator having a heat-resistant temperature of 140 ° C. and a thickness of 20 μm to form a spiral electrode group. Produced. As shown in FIG. 2, this electrode group was pressed so that the cross section was substantially elliptical.
[0035]
(Iv) Arrangement of Insulating Member Next, as shown in FIGS. 1 and 2, a double-sided current collector exposed portion located on the outermost periphery of the electrode group, and a single-sided current collector exposed portion located on the inner side of the circumference, An insulating member 5 was disposed inside the separator 3 between the two. The width of the insulating member 5 was 2 mm larger than the width of the positive electrode current collector 1a, and protruded from the upper end and the lower end of the positive electrode 1 by 1 mm each.
Here, as the insulating member, an insulating tape composed of a base material of polyphenylene sulfide resin (heat resistant temperature 200 ° C.) having a thickness of 20 μm and a glue layer of urethane resin having a thickness of 10 μm formed on one surface thereof was used. The insulating tape was attached to the single-sided current collector exposed portion of the positive electrode 1.
[0036]
(V) Battery assembly The electrode group was housed in a bottomed rectangular battery case 4 having an opening. The other end of the positive electrode lead 1c was connected to a sealing plate having an explosion-proof mechanism, and the other end of the negative electrode lead 2c was connected to a negative electrode terminal of the sealing plate. Thereafter, the periphery of the sealing plate and the open end of the battery case 4 were laser welded.
[0037]
Next, a nonaqueous electrolytic solution was injected into the battery case 4 from the injection hole of the sealing plate. This non-aqueous electrolyte is obtained by dissolving lithium hexafluorophosphate (LiPF 6 ) as a solute at a concentration of 1.0 mol / L in a mixed solvent of ethylene carbonate and ethyl methyl carbonate in a volume ratio of 1: 1. It is. Thereafter, a plug was inserted into the liquid injection hole, and the battery was sealed by laser welding the periphery of the plug and the sealing plate. Thus, a prismatic lithium ion secondary battery (width 5.3 mm, length 30 mm, total height 48 mm) having a nominal capacity of 800 mAh was completed. 100 similar batteries were produced.
[0038]
<< Comparative Example 1 >>
A rectangular lithium ion secondary battery (width 5.3 mm, length 30 mm, total height 48 mm) having a nominal capacity of 800 mAh was produced in the same manner as in Example 1 except that no insulating member was provided in the electrode group. did. 100 similar batteries were produced.
[0039]
[Evaluation]
The rate of occurrence of internal short-circuits immediately after the assembly of each battery of Example 1 and Comparative Example 1 (occurrence rate A: out of 100, the number of batteries with internal short-circuits), and after conducting a high-temperature storage test in a charged state The occurrence rate of internal short circuit (occurrence rate B: the number of batteries in which internal short circuit occurred out of 10) was evaluated. The results are shown in Table 1.
[0040]
In the high-temperature storage test, each battery was discharged at a constant current of 160 mA to a final voltage of 3.0 V in an environment of 20 ° C., and then charged at a constant voltage and a constant voltage of a charging voltage of 4.2 V and a charging current of 80 mA. . Then, the fully charged battery was stored in an atmosphere at 80 ° C. for one week.
[0041]
[Table 1]
Figure 0003821434
[0042]
From Table 1, it can be seen that in Example 1, the rate of occurrence of internal short circuit is extremely low immediately after assembly and after storage at high temperature. On the other hand, in Comparative Example 1, the incidence of internal short circuiting is very high immediately after assembly and after storage at high temperature. Only in Example 1, the difference is that the insulating member 5 is placed between the double-sided current collector exposed portion located on the outermost periphery of the electrode group and the single-sided current collector exposed portion located on the inner side of the circumference. This is considered to be the effect of the arrangement. That is, in Example 1, local pressure is eased at the step portion formed by the longitudinal end portion of the separator and the peripheral edge portion of the positive electrode lead in the electrode group, the non-uniformity of the electrode reaction is reduced, and the positive electrode active material It is considered that the elution of was suppressed and internal short circuit was prevented.
[0043]
【The invention's effect】
According to the present invention, the local pressure generated in the stepped portion formed in the electrode group is alleviated and the non-uniformity of the electrode reaction is reduced, thereby preventing the internal short circuit of the battery. Therefore, the productivity and reliability of the non-aqueous electrolyte secondary battery having a high energy density are improved.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view of an electrode group according to an example of an embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of a non-aqueous electrolyte secondary battery using an electrode group according to an example of an embodiment of the present invention.
FIG. 3 is a partial cross-sectional view of a conventional electrode group.
4 is a front view of a region A including a short-circuit portion 15 in a negative electrode in the electrode group shown in FIG. 3 as viewed from the direction of an arrow X. FIG.
FIG. 5 is a cross-sectional view of a positive electrode used for an electrode group according to an example of an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 11 Positive electrode 1a, 11a Positive electrode collector 1b, 11b Positive electrode mixture layer 1c, 11c Positive electrode lead 2, 12 Negative electrode 2a, 12a Negative electrode collector 2b, 12b Negative electrode mixture layer 2c Negative electrode lead 3, 13 Separator 4, 14 Battery case 5 Insulating members 9, 19 Separator longitudinal end 15 Short-circuit portion 16 Border line 17 of the opposing area between the negative electrode and the positive electrode Border line 18 of the opposing area between the area A and the longitudinal end of the separator Area A and the positive electrode lead The boundary line 51 of the area opposite to the double-sided collector exposed portion 52 Single-sided collector exposed portion

Claims (4)

正極と負極とを、それらの間にセパレータを介して捲回してなる渦巻き状の電極群であって、
前記正極は、正極集電体および前記正極集電体上に設けられた少なくとも１つの正極合剤層からなり、
前記負極は、負極集電体および前記負極集電体上に設けられた少なくとも１つの負極合剤層からなり、
前記電極群の最外周を構成する前記正極および前記負極のどちらか一方において、外周側の長手方向における端部から内周側の所定位置までの領域が、両面に合剤層が設けられていない両面集電体露出部であり、
前記両面集電体露出部に続くさらに内周側の所定位置までの領域が、内側片面のみに合剤層が設けられている片面集電体露出部であり、
前記両面集電体露出部と前記片面集電体露出部とが、少なくとも部分的に、前記最外周を構成しない他方の電極を介さずに対向しており、
前記両面集電体露出部には、リードが接続されており、
前記リードよりも内周側に、前記セパレータの外周側の長手方向における端部が位置しており、
前記最外周を構成する電極の外周側の長手方向における端部および前記セパレータの外周側の長手方向における端部がそれぞれ前記電極群内で形成する段差部分が、内側から絶縁部材により覆われている電池用電極群。A spiral electrode group formed by winding a positive electrode and a negative electrode with a separator between them,
The positive electrode comprises a positive electrode current collector and at least one positive electrode mixture layer provided on the positive electrode current collector,
The negative electrode comprises a negative electrode current collector and at least one negative electrode mixture layer provided on the negative electrode current collector,
In either one of the positive electrode and the negative electrode constituting the outermost periphery of the electrode group, the region from the end in the longitudinal direction on the outer peripheral side to a predetermined position on the inner peripheral side is not provided with a mixture layer on both sides A double-sided current collector exposed part,
The region up to a predetermined position on the inner peripheral side following the double-sided current collector exposed portion is a single-sided current collector exposed portion in which a mixture layer is provided only on the inner side surface,
The double-sided current collector exposed portion and the single-sided current collector exposed portion are opposed at least partially without the other electrode that does not constitute the outermost periphery,
A lead is connected to the double-sided current collector exposed portion,
The end in the longitudinal direction of the outer peripheral side of the separator is located on the inner peripheral side of the lead,
The step portion fraction ends in the longitudinal direction of the outer peripheral side of the end portion and the separator in the longitudinal direction of the outer peripheral side of the electrode constituting the outermost periphery is formed within each of said electrode group, covered by the inner insulating member Battery electrode group. 前記絶縁部材が、前記段差部分と対向する片面集電体露出部の外側に、貼り付けられている請求項１記載の電池用電極群。The battery electrode group according to claim 1, wherein the insulating member is affixed to the outside of a single-sided current collector exposed portion that faces the stepped portion. 正極と負極とを、それらの間にセパレータを介して捲回してなる渦巻き状の電極群、非水電解液および前記電極群と前記非水電解液とを収容する電池ケースからなり、A spiral electrode group formed by winding a positive electrode and a negative electrode with a separator between them, a non-aqueous electrolyte, and a battery case containing the electrode group and the non-aqueous electrolyte,
前記正極は、正極集電体および前記正極集電体上に設けられた少なくとも１つの正極合剤層からなり、  The positive electrode comprises a positive electrode current collector and at least one positive electrode mixture layer provided on the positive electrode current collector,
前記負極は、負極集電体および前記負極集電体上に設けられた少なくとも１つの負極合剤層からなり、  The negative electrode comprises a negative electrode current collector and at least one negative electrode mixture layer provided on the negative electrode current collector,
前記電極群の最外周を構成する前記正極および前記負極のどちらか一方において、外周側の長手方向における端部から内周側の所定位置までの領域が、両面に合剤層が設けられていない両面集電体露出部であり、  In either one of the positive electrode and the negative electrode constituting the outermost periphery of the electrode group, the region from the end in the longitudinal direction on the outer peripheral side to a predetermined position on the inner peripheral side is not provided with a mixture layer on both sides A double-sided current collector exposed part,
前記両面集電体露出部に続くさらに内周側の所定位置までの領域が、内側片面のみに合剤層が設けられている片面集電体露出部であり、  The region up to a predetermined position on the inner peripheral side following the double-sided current collector exposed portion is a single-sided current collector exposed portion in which a mixture layer is provided only on the inner side surface,
前記両面集電体露出部と前記片面集電体露出部とが、少なくとも部分的に、前記最外周を構成しない他方の電極を介さずに対向しており、  The double-sided current collector exposed portion and the single-sided current collector exposed portion are opposed at least partially without the other electrode that does not constitute the outermost periphery,
前記両面集電体露出部には、リードが接続されており、  A lead is connected to the double-sided current collector exposed portion,
前記リードよりも内周側に、前記セパレータの外周側の長手方向における端部が位置しており、  The end in the longitudinal direction of the outer peripheral side of the separator is located on the inner peripheral side of the lead,
前記最外周を構成する電極の外周側の長手方向における端部および前記セパレータの外周側の長手方向における端部がそれぞれ前記電極群内で形成する段差部分が、内側から絶縁部材により覆われている非水電解液二次電池。  Step portions formed in the electrode group by the end portion in the longitudinal direction on the outer peripheral side of the electrode constituting the outermost periphery and the end portion in the longitudinal direction on the outer peripheral side of the separator are covered with an insulating member from the inside. Non-aqueous electrolyte secondary battery. 前記絶縁部材が、前記段差部分と対向する片面集電体露出部の外側に、貼り付けられている請求項３記載の非水電解液二次電池。The non-aqueous electrolyte secondary battery according to claim 3, wherein the insulating member is affixed to the outside of the single-sided current collector exposed portion that faces the stepped portion.
JP2002285844A 2002-09-30 2002-09-30 Battery electrode group and non-aqueous electrolyte secondary battery using the same Expired - Lifetime JP3821434B2 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
JP2002285844A JP3821434B2 (en) 2002-09-30 2002-09-30 Battery electrode group and non-aqueous electrolyte secondary battery using the same
US10/664,879 US7425386B2 (en) 2002-09-30 2003-09-22 Electrode group for battery and non-aqueous electrolyte secondary battery using the same
EP03021956.2A EP1437779B1 (en) 2002-09-30 2003-09-29 Electrode group for battery and non-aqueous electrolyte secondary battery using the same
CNB031327192A CN1231983C (en) 2002-09-30 2003-09-30 Electrode set for battery and non aqueous electrolyte accumulator cell using electrode set of said. battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2002285844A JP3821434B2 (en) 2002-09-30 2002-09-30 Battery electrode group and non-aqueous electrolyte secondary battery using the same

Publications (3)

Publication Number Publication Date
JP2004127541A JP2004127541A (en) 2004-04-22
JP2004127541A5 JP2004127541A5 (en) 2005-10-20
JP3821434B2 true JP3821434B2 (en) 2006-09-13

Family

ID=32025345

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2002285844A Expired - Lifetime JP3821434B2 (en) 2002-09-30 2002-09-30 Battery electrode group and non-aqueous electrolyte secondary battery using the same

Country Status (4)

Country Link
US (1) US7425386B2 (en)
EP (1) EP1437779B1 (en)
JP (1) JP3821434B2 (en)
CN (1) CN1231983C (en)

Families Citing this family (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005310619A (en) * 2004-04-23 2005-11-04 Matsushita Electric Ind Co Ltd Lithium-ion secondary battery
JP4657001B2 (en) * 2004-05-25 2011-03-23 パナソニック株式会社 Lithium ion secondary battery and manufacturing method thereof
KR100579376B1 (en) * 2004-10-28 2006-05-12 삼성에스디아이 주식회사 Secondary battery
JP4591674B2 (en) * 2004-11-08 2010-12-01 ソニー株式会社 Lithium ion secondary battery
TWI291778B (en) * 2004-11-08 2007-12-21 Sony Corp Secondary battery
JP4649993B2 (en) * 2005-01-12 2011-03-16 パナソニック株式会社 Lithium secondary battery and manufacturing method thereof
JP4891555B2 (en) * 2005-03-14 2012-03-07 三井金属鉱業株式会社 Method for producing non-aqueous electrolyte secondary battery
JP4863636B2 (en) * 2005-03-29 2012-01-25 三洋電機株式会社 Spiral electrode square battery
JP5148142B2 (en) * 2007-03-15 2013-02-20 日立マクセルエナジー株式会社 Non-aqueous electrolyte battery
US8076026B2 (en) * 2010-02-05 2011-12-13 International Battery, Inc. Rechargeable battery using an aqueous binder
US7931985B1 (en) * 2010-11-08 2011-04-26 International Battery, Inc. Water soluble polymer binder for lithium ion battery
US20110143206A1 (en) * 2010-07-14 2011-06-16 International Battery, Inc. Electrode for rechargeable batteries using aqueous binder solution for li-ion batteries
US8102642B2 (en) * 2010-08-06 2012-01-24 International Battery, Inc. Large format ultracapacitors and method of assembly
US9171674B2 (en) * 2011-04-06 2015-10-27 Empire Technology Development Llc Ionic electron conductive polymer capacitor
US10014518B2 (en) * 2012-12-28 2018-07-03 Johnson Controls Technology Company Cathode formed using aqueous slurry
CN110544796B (en) * 2018-05-28 2022-09-02 株式会社村田制作所 Secondary battery, battery pack, electric vehicle, electricity storage system, electric tool, and electronic device
KR102144571B1 (en) * 2018-10-24 2020-08-14 울산과학기술원 Electrode structure, manufacturing method of the same, secondary battery including the same

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05182691A (en) 1991-12-28 1993-07-23 Sony Corp Nonaqueous electrolyte secondary battery
GB2324404A (en) 1997-04-18 1998-10-21 Alexander Gilmour Sealed duplex electrode electrochemical cell
JPH11273739A (en) 1998-03-19 1999-10-08 Sony Corp Nanaqueous electrolyte secondary battery
CN1330019C (en) 1998-11-06 2007-08-01 株式会社杰士汤浅 Nonaqueous secondary electrolytic battery
EP2315300B1 (en) 1999-09-30 2017-07-19 Sony Corporation Solid electrolyte cell

Also Published As

Publication number Publication date
EP1437779A2 (en) 2004-07-14
EP1437779A3 (en) 2006-10-04
CN1497755A (en) 2004-05-19
US20040062982A1 (en) 2004-04-01
EP1437779B1 (en) 2013-04-17
JP2004127541A (en) 2004-04-22
US7425386B2 (en) 2008-09-16
CN1231983C (en) 2005-12-14

Similar Documents

Publication Publication Date Title
US7935445B2 (en) Lithium ion secondary battery
KR100958649B1 (en) Battery unit and the winding method thereof and lithum secondary battery using the same
EP2293367B1 (en) Rechargeable secondary battery having improved safety against puncture and collapse
JP3821434B2 (en) Battery electrode group and non-aqueous electrolyte secondary battery using the same
JP4617065B2 (en) Lithium ion secondary battery
KR101664244B1 (en) Method forming electrode surface pattern and the electrode manufactured by the method and secondary battery including the same
JP2006278142A (en) Square battery with spiral electrode
JPWO2009144919A1 (en) Cylindrical non-aqueous electrolyte secondary battery
WO2013099295A1 (en) Cylindrical lithium-ion cell
JP5571318B2 (en) Cylindrical battery
US20050058896A1 (en) Non-aqueous electrolyte secondary battery
JP2003092148A (en) Nonaqueous secondary battery
JPH10241699A (en) Battery
CN109891640B (en) Electrode for nonaqueous electrolyte secondary battery and nonaqueous electrolyte secondary battery
JP2006079942A (en) Battery
JP4245429B2 (en) Battery with spiral electrode group
JP2000357505A (en) Nonaqueous electrolyte secondary battery
JP3700683B2 (en) Non-aqueous electrolyte secondary battery
WO2022266894A1 (en) Electrochemical device and electronic device
JP4069988B2 (en) Lithium ion secondary battery
JP2000285905A (en) Thin battery
JP3414729B1 (en) Lithium ion secondary battery
JP2005123058A (en) Nonaqueous electrolyte secondary battery
KR100601563B1 (en) Cylindrical lithium ion secondary battery
JP2003022791A (en) Lithium secondary battery

Legal Events

Date Code Title Description
A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20050628

A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20050628

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20060420

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20060615

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20060616

R150 Certificate of patent or registration of utility model

Free format text: JAPANESE INTERMEDIATE CODE: R150

Ref document number: 3821434

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20100630

Year of fee payment: 4

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20100630

Year of fee payment: 4

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20110630

Year of fee payment: 5

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20120630

Year of fee payment: 6

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20120630

Year of fee payment: 6

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20130630

Year of fee payment: 7

EXPY Cancellation because of completion of term